

Front  Back  
Statistics (the science)

 
Statistic (singular)

 
Descriptive Statistics vs. Inferential Statistics

 
Correlational Method vs. Experimental Method

 
Experimental Group vs. Control Group

 
Sample

 
Data (plural) vs. Datum/score/raw score (singular)
vs. Information 
 
Data Set

 
Variables vs. Constants

 
Values vs. Value Categories

 
Frequency

 
Conceptualization vs. Operationalization

 
Reliability vs. Validity

Reliability: the degree of consistency of a measurement p. 07
Validity: when measurement is both reliable (consistent) AND truly measuring what it is believed to be measuring. p. 07  
Research Hypotheses

a statement that we make about what we believe to be the relationship between or among variables. p. 08
 
onetailed hypothesis vs. twotailed hypothesis vs. null hypothesis

 
most frequently used type of research hypothesis by social workers

 
Positive Correlation vs. Negative Correlation

 
Independent Variable vs. Dependent Variable

 
Variable Levels of measurement (4)

 
(1) Nominal Level variable Measurement

 
(2) Ordinal Level variable Measurement

 
(3) Interval Level variable Measurement

 
(4) Ratio Level variable Measurement

 
Categorical/Discrete Variables vs. Continuous Variables

 
Dichotomous variable

 
Population

 
Parameter

 
CHAPTER 02  Frequency Distributions and Graphs


Frequency Distribution

 
Percentile vs. Percentile Rank

Percentile: a point below which a certain percentage of the distribution of values lies. each z score corresponds to both a certain z score and a certain percentile rank
Percentile Rank: tells us approximately what percentage of scores falls above or below the raw score  
Bar Graph

A graph showing a bar above each score or interval so that the height of the bar corresponds to the frequency. A space is left between adjacent bars.
 
Line Graph

Points connected with straight lines to form a graph
Ch 3, pg 79  
Histogram

A graph showing a bar above each scoreor interval so that the height of the bar corresponds to the frequency and width extends to the real limits.
 
Polygon

A fraph consisting of a line that connects a series of dots. A dot is placed above each score or intervalso that the height of the dot corresponds to the frequency.
 
CHAPTER 03  Measures of Central Tendency and Variability


Central Tendancy

A statistical measurement to determinea single score that defines the center of a distribution  a single score that is most represetitive of the group.
 
Mode

The score or category in a frequency distrbution that has the greatest frequency
Ch 3, pg 73  
Bimodal

A distribution with two modes (catagories that has the greatest frequency)
Ch 3, pg 74  
Multimodal

A distribution with more than two sets of modes (catagories that have the greatest frequency)
Ch 3, pg 74  
Median

If a distribution is listed from smallest to largest, median is the midpoint of the list.
 
Mean

The sum of scores in a distribution, divided by the number of scores.
 
Measures of Variability (5)

 
Range

the distance that encompasses all values within a data set; (maximum value  minimum value + 1)
 
why do we add 1 to the difference between the maximum value and the minimum value when determining range?

so that the range reflect the total number of vales of the variable that it encompasses
 
mean deviation

the average amount that the values of a variable differ (or deviate) from the mean; describes only the amount of variation among values of a variable, not their absolute values
 
how to configure a deviation value

subtract raw scores from the mean
 
mean deviation formula

mean deviation = sum of deviation values (ignoring sign)/number of cases
 
variance formula

variance = the sum of the square of each deviation value/total number of values minus one (for sample data) or simply the total number of values (for population data)
 
how to configure the variance

subtract the mean of the distribution from each value (getting the mean deviation) then square each difference. Divide the sum of the squared differences (called the sum of squares) by either the total numbr of values minus one (for sample data) or simply the total number of values (for population data)
 
standard deviation

the square root of the varience; used for describing the variability of a data set; requires interval level or ratio level data and a normal distribution; reflects variation, and the amount of variation does not change
 
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